Ice making system and method for ice making of refrigerator

ABSTRACT

The present disclosure provides a refrigerant pipe, through which low temperature and low pressure refrigerant flows, directly on a tray, allowing for quick ice formation even when an ice maker is installed in a refrigeration compartment, and allowing for transparent chunks of ice to be made.

TECHNICAL FIELD

The present disclosure relates to an ice making system and an ice making method of a refrigerator.

BACKGROUND ART

In general, a refrigerator is a home appliance that stores food at low temperatures to keep the food fresh for a prolonged period.

Specifically, a refrigerator provides a refrigeration compartment that maintains an inside temperature within a range of 1-4° C. to preserve foods such as vegetables in a fresh state, and a freezer compartment that maintains an inside temperature of around −18° C. to preserve foods such as meat and fish in a frozen state.

Refrigerators may be divided according type into top mount refrigerators with the freezer compartment above the refrigeration compartment, bottom freezer refrigerators with the freezer compartment below the refrigeration compartment, and side by side refrigerators with the freezer and refrigeration compartments provided beside one another.

Refrigerators can also be divided into french door refrigerators with doors mounted on the left and right, and top-bottom door refrigerators.

Some refrigerators have an ice maker for making ice provided on a side of the refrigeration or freezer compartment, and an ice bank for storing ice that is made.

In detail, when an ice maker and an ice bank are provided on the freezer compartment, water stored in the ice maker is converted to ice by refrigerant that passes through an evaporator, and the ice that is formed descends into and is stored in the ice bank provided below the ice maker.

When an ice maker and ice bank are provided in the refrigeration compartment, because the inside of the refrigeration compartment is maintained at temperatures above freezing, it is difficult to form ice with refrigerant supplied for use in the refrigeration compartment. In other words, if an ice maker is provided inside the refrigeration compartment, ice cannot be completely formed, or formed ice will melt quickly when removed. Therefore, in order to provide an ice maker in the refrigeration compartment, a thermally insulating case that isolates the ice maker from the atmosphere within the refrigeration compartment must be provided also.

DISCLOSURE OF INVENTION Technical Problem

According to an object of the present disclosure, there are provided an ice making system and an ice making method for a refrigerator, capable of easily making ice even with an ice maker that is provided within a refrigeration compartment. That is, an object of the present disclosure is to provide an ice making system and an ice making method for a refrigerator that do not require a separate thermally insulating case enclosing the ice maker even when the ice maker is provided within a refrigeration compartment.

According to another object of the present disclosure, there are provided an ice making system and an ice making method for a refrigerator that shorten the time required for making ice and form transparent ice chunks, even when the ice maker is provided in the refrigeration compartment.

According to a further object of the present disclosure, there are provided an ice making system and an ice making method for a refrigerator that allow ice to be easily separated from the ice maker after its formation is complete.

Technical Solution

To achieve the above objects, embodiments of the present disclosure provide an ice making system for a refrigerator including: a compressor compressing refrigerant; a condenser through which refrigerant that passes through the compressor flows; an expander expanding refrigerant that passes through the condenser to a low temperature and low pressure state; a tray provided within a refrigeration chamber to store water for ice making therein and move during at least an ice separation process; and a freezing pipe branched from an outlet of the expander and connected to an inlet of the compressor, and having at least a portion thereof immersed in the water stored in the tray, wherein ice is made directly on a surface of the freezing pipe.

In another aspect of the present disclosure, there is provided an ice making system for a refrigerator including: a tray filled with potable water for making ice, and provided in a space maintained at an above-freezing temperature; and a freezing pipe with at least a portion thereof immersed in the water filled in the tray, wherein in an ice making process, low temperature refrigerant flows to the freezing pipe, and ice is made directly on a surface of the freezing pipe.

Additionally, in order to achieve the above objects, embodiments of the present disclosure provide an ice making method for a refrigerator, including: collecting water for ice making in a tray provided in a refrigeration compartment, the tray containing a freezing pipe in a space within; immersing at least a portion of the freezing pipe in the water; forming ice on a surface of the freezing pipe by inducing a flow of low temperature refrigerant through the freezing pipe; removing residual water from the tray when the forming of the ice is completed; and detaching the ice formed on the surface of the freezing pipe.

Advantageous Effects

As described above, in an ice making system and ice making method for a refrigerator according to the present disclosure, because a separate duct for supplying cold air to the ice maker does not need to be formed, the manufacturing process of the refrigerator is simplified and the manufacturing cost of the refrigerator is also reduced.

Also, because a portion of refrigerant used in a freezing cycle of the refrigerator is used for ice making, additional energy is not required for ice making, thus providing an energy saving benefit.

In addition, even with the ice maker provided in the refrigeration compartment, ice making is properly performed.

Furthermore, because a separate thermally insulating case isolating the ice maker from the atmosphere inside the refrigeration compartment is not needed, the inner dimensions of the refrigeration compartment can easily be expanded.

Moreover, because there is no need to separately form a passage to supply a portion of refrigerant to the ice maker in order to make ice, the interior of the refrigeration compartment or the space in the freezer compartment can be enlarged.

Additionally, with the above structures, transparent ice chunks can easily be made.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a frontal view of a refrigerator provided with an ice maker according to an embodiment of the present disclosure.

FIG. 2 is a side sectional view of a refrigerator according to an embodiment of the present disclosure.

FIG. 3 is a perspective view showing a schematic structure of an ice maker according to a first embodiment of the present disclosure.

FIG. 4 is a diagram showing a refrigerant cycle for an ice maker according to the first embodiment of the present disclosure.

FIGS. 5 to 8 are sectional views showing ice making and ice separating processes in an ice maker according to the first embodiment of the present disclosure.

FIG. 9 is a perspective view showing a schematic structure of an ice maker according to a second embodiment of the present disclosure.

FIG. 10 is diagram showing a refrigerant cycle for an ice making system according to the second embodiment of the present disclosure.

FIGS. 11 to 14 are sectional views showing ice making and ice separating processes in an ice maker according to the second embodiment of the present disclosure.

MODE FOR THE INVENTION

Reference will now be made in detail to specific embodiments of the present disclosure, with reference to the accompanying drawings. It should be understood, however, that the scope of the present disclosure is not limited to the embodiments described herein, and that through various additions, modifications, and deletions of elements, alternate embodiments that fall within the scope of regressive inventions or the present disclosure may be easily provided.

FIG. 1 is a frontal view of a refrigerator provided with an ice maker according to an embodiment of the present disclosure, and FIG. 2 is a side sectional view of a refrigerator according to an embodiment of the present disclosure.

Referring to FIGS. 1 and 2, a refrigerator according to the present disclosure is exemplarily described as a bottom freezer refrigerator having the refrigeration compartment provided at the top and the freezer compartment provided therebelow.

In detail, a refrigerator 10 according to the present disclosure includes a main body 11 provided with a refrigeration compartment 15 and a freezer compartment 16, refrigeration compartment doors 12 opening and closing the refrigeration compartment 15, and a freezer compartment door 13 opening and closing the freezer compartment 16. That is, the refrigeration compartment 15 and the freezer compartment 16 are separated by a barrier 111.

The refrigerator 10 also includes a compressor 32 provided at the bottom of the main body 11 to compress refrigerant, an evaporator 31 disposed at the rear of the main body 11 to generate cold air, and a blower fan 33 for supplying the cold air generated by the evaporator 31 to the refrigeration compartment 15 and the freezer compartment 16.

The refrigerator 10 further includes a freezer duct 17 through which the cold air blown by the blower fan 33 is supplied to the freezer compartment, a refrigeration duct 18 through which cold air is supplied to the refrigeration compartment 15, an ice maker 20 provided at the ceiling of the refrigeration compartment 16, and an ice bank 21 for storing ice made by the ice maker 20. Also, a dispenser 14 is provided at the front of one of the refrigeration compartment doors 12 to supply filtered water or the ice stored in the ice bank 21 to the outside.

Specifically, a plurality of cold air holes is provided in the freezer duct 17, through which cold air is discharged into the freezer compartment 16. Here, the evaporator 31 and the blower fan 33 may not only be configured inside the freezer duct 17, but the evaporator 31 and blower fan 33 may be provided in a separate space within the main body 11, and the freezer duct 17 connected to the freezer compartment 16 may be separately formed.

The refrigeration duct 18 may extend from a space in which the evaporator 31 is contained, extend through the barrier 111, and be connected to the refrigeration compartment 15. Here, the refrigeration duct 18 may also be configured to communicate directly with the space in which the evaporator 31 is contained, or may be branched from the freezer duct 17.

The freezer compartment door 13 is provided as a drawer, and a removable basket 29 for storing frozen food is provided behind the freezer compartment door 13.

In detail, the frame of the door extends rearward from either side at the rear of the freezer compartment door 13, and the door frame and the sides of the freezer compartment door 16 are connected through rail members. Thus, the freezer compartment door 13 is horizontally withdrawable along the rail members.

In the above configuration, ice that is made in the ice maker 20 provided on the ceiling of the refrigeration compartment 15 is separated from a tray (described below), and drops into the ice bank 21. Here, while not shown, a guide extending from the ice maker 20 or from the ice bank 21 may be provided to allow the ice separated from the ice maker 20 to reliably drop into the ice bank 21.

In detail, the top of the ice bank 21 is open, and the open portion of the ice bank 21 is disposed below the ice maker 20 when the refrigeration compartment door 12 is closed.

When the ice bank 21 is provided in the refrigeration compartment 15 or on the refrigeration compartment door 12, chunks of ice can melt and stick together in the above-zero temperature that is maintained in the refrigeration compartment.

To obviate the above limitation, there is a need to prevent melting of ice by maintaining the temperature within the ice bank 21 at sub-zero temperatures.

Below, a preferred embodiment will be described for maintaining the inside of the ice bank 21 so that ice does not melt.

A refrigerator 10 according to the present disclosure is configured to have an ice maker 20 and an ice bank 21 disposed within the refrigeration compartment.

In detail, the ice bank 21 includes a cylindrical container 211 open at the top, an auger 212 provided in the bottom of the container 211 to guide ice downward, a crusher 213 integrally extending from the bottom of the auger 212 to crush ice, a motor 214 driving the crusher 213, and a shaft 215 connecting the motor 214 to the crusher 213 to transmit the rotating force of the motor. Here, the container 211 is not restricted to having a cylindrical shape, and containers of various shapes may be alternately provided.

The ice maker 20 is provided on one side of the ceiling portion of the refrigeration compartment 15. The ice maker 20 is disposed above the ice bank 21, so that discharged ice can descend into the container 211. The configuration of the ice maker 20 and an ice making method will be described below with reference to the diagrams.

The refrigeration duct 18 communicates with a space that holds the evaporator 31, and extends along a wall of the refrigeration compartment 15 toward the ceiling portion of the refrigeration compartment 15. The end of the refrigeration duct 18 extends to the front of the refrigeration compartment 15, forming a structure above the container 211. Thus, cold air flowing through the refrigeration duct 18 is discharged forward, and a portion of the discharged cold air descends into the container 211, and the remainder circulates within the refrigeration compartment 15.

In the above structure, at least a portion of cold air that became cold as it passes through the evaporator 31 is directly discharged into the container 211, so that ice stored in the container 211 is prevented from melting and sticking together.

The refrigeration duct 18 extends to the front of the refrigeration compartment 15, and the end thereof is bent at a predetermined angle to discharge cold air downward. Accordingly, the cold air discharged from the refrigeration duct 18 is discharged downward from the front of the refrigeration compartment 15, providing the effect of an air curtain.

Another method for preventing melting and sticking together of ice stored in the container 211 involves surrounding the surface of the container 211 with a cold accumulating member, which may be built into the container 211. Also, a separate cooling means may be installed around the container 211—for example, on the floor of the container 211.

FIG. 3 is a perspective view showing a schematic structure of an ice maker according to a first embodiment of the present disclosure.

Referring to FIG. 3, an ice maker 20 according to a first embodiment of the present disclosure includes a tray 201 that stores water used for making ice, a freezing pipe 40 extending into the tray 201, and a water supplying device for supplying water to the tray 201.

Specifically, the water supplying device includes a water tank 42 storing water, a pump 41 that pumps water within the water tank 42, and a water supplying pipe 43 extending from the pump 41 to the tray 201. Also, a dispenser connecting pipe 44 may branch off from a side of the water supplying pipe 43, and a redirecting valve 45 may be installed at the branching point to selectively control the flow direction of water. In more detail, the dispenser connecting pipe 44 extends toward the dispenser to dispense drinking water to users.

A pivoting axis 202 extends at either side of the tray 201, so that the pivoting axes 202 may be inserted into the inner walls of the the refrigeration compartment at which the tray 201 is installed.

The freezing pipe 40 is a pipe through which a portion of refrigerant within a cold air cycle flows, and forms protruding portions 401 (as shown) by being bent or curved a plurality of times. A part of each protruding portion 401 is immersed in water stored in the tray 201. The structure of the freezing pipe 40 will be described in more detail with reference to the diagrams.

To briefly describe an ice making process through the above configuration, low temperature refrigerant flows through the freezing pipe 40, and water within the tray 201 is frozen on the surface of the protruding portions 401. At a certain point, the water remaining in the tray 201 is removed, and then high temperature refrigerant flows through the freezing pipe 40. Thus, the ice formed on the surfaces of the protruding portions 401 is separated, and the separated ice drops into the ice bank 21.

FIG. 4 is a diagram showing a refrigerant cycle for an ice maker according to the first embodiment of the present disclosure.

Referring to FIG. 4, an ice making system for a cold air cycle according to the first embodiment of the present disclosure includes a compressor 32 that compresses refrigerant, a condenser 34 that condenses refrigerant compressed by the compressor 32 to a high temperature and high pressure, an expander 35 that expands the refrigerant condensed by the condenser 34 to a low temperature and low pressure, and an evaporator 31 in which the refrigerant that passes through the expander 35 exchanges heat with air. The compressor 32, condenser 34, expander 35, and evaporator 31 are connected through a refrigerant pipe 39.

In detail, a blower fan 33 is provided at a side of the evaporator 31, to supply air that has passed through the evaporator and become cold to the refrigeration compartment or the freezer compartment. The freezing pipe 40 branches from the outlet of the expander 35, and the outlet of the freezing pipe 40 branches to connect respectively to the outlet of the evaporator 31 and the inlet of the condenser 34. A first valve 36 is installed at the point where the freezing pipe 40 branches from the outlet of the expander 35, and a portion of refrigerant passing through the expander 35 is selectively controlled to flow to the freezing pipe 40. Also, a return pipe 47 branches from the outlet of the freezing pipe 40 and connects to the inlet of the condenser 34. A third valve 38 is provided at the point where the return pipe 37 branches, and refrigerant is selectively controlled to flow to one of the outlet of the evaporator 31 and the inlet of the condenser 34, an ice separation pipe 46 branches from the outlet of the compressor 32 and extends to the inlet of the freezing pipe 40. A second valve 37 is provided at the point where the ice separation pipe 46 and the inlet of the freezing pipe 40 meet, to selectively control the flow of a portion of high temperature and high pressure refrigerant to the freezing pipe 40. Of course, a separate opening and closing valve may be installed at the inlet at which the ice separation pipe 46 branches.

Because ice is formed directly on the surface of the freezing pipe 40, the surface of the freezing pipe 40 must be kept clean. That is, in order to prevent metal impurities from mixing with ice that is separated, the freezing pipe 40 must be made of a material known to be safe. Therefore, the freezing pipe 40 may be formed of a rust-resistant material or a corrosion-resistant material, or the surface of the freezing pipe 40 may be treated by being coated with a rust-resistant or corrosion-resistant material.

The refrigerant circulating processes for freezing and ice separation procedures of the above-configured cold air system will now be described.

First, when the refrigerator operates, a freezing cycle is performed. In other words, refrigerant is compressed by the compressor 32 to a high temperature and high pressure gaseous refrigerant, and the compressed refrigerant passes through the condenser 34 to exchange heat with external air and convert to high temperature and high pressure liquid refrigerant. Then, the refrigerant that passes through the condenser 34 passes through the expander 35 to convert into a second phase refrigerant of low temperature and low pressure. Next, the low temperature and low pressure second phase refrigerant passes through the evaporator 31 to exchange heat with air and convert to a low temperature and low pressure gaseous refrigerant. The air that exchanges heat with the evaporator 31 becomes cold and is supplied by the blower fan 33 to the refrigeration compartment or the freezer compartment. The refrigerant that passes through the evaporator 31 re-enters the compressor 32 to complete the cycle.

In detail, a portion of the refrigerant flows along line ‘a’ during the ice making process, and a portion of the refrigerant flows along line ‘b’ in the ice separation process.

In further detail, while the ice making process is being performed, the opened degree of the first valve 36 is adjusted to permit a portion of the refrigerant passing through the expander 35 to be supplied to the freezing pipe 40. The refrigerant that passes through the freezing pipe 40 freezes the water stored in the tray 201. Also, the opened degree of the third valve 38 is adjusted to permit the refrigerant passing through the freezing pipe 40 to flow to the evaporator 31 and re-enter the compressor 32.

When the ice making process is complete and the ice separation process begins, the first valve 36 is opened to stop the supply of low temperature, low pressure refrigerant to the freezing pipe 40. Also, the second valve 37 is controlled to supply high temperature, high pressure gaseous refrigerant along the ice separation pipe 46 to the freezing pipe 40. Thus, the temperature of the freezing pipe 40 rises so that the ice stuck to the protruding portions 401 of the freezing pipe 40 disengages.

Also, the opened degree of the third valve 38 is controlled in the ice separation process to allow refrigerant passing through the freezing pipe 40 to flow to the return pipe 47 and flow into the inlet of the condenser 34.

Here, the point at which the outlet end of the freezing pipe 40 is connected is not limited to the depictions in the diagrams, and may be altered. Also, in addition to the method in which the refrigerant passing through the compressor to the freezing pipe 40 in the ice separation process, a cycle may be provided in which the refrigerant passes through the condenser.

FIGS. 5 to 8 are sectional views showing ice making and ice separating processes in an ice maker according to the first embodiment of the present disclosure.

Referring to FIG. 5, water supplied to the water tank 42 through the pump 41 is supplied to the tray 201 through the water supplying pipe 43. Of course, water is supplied from an external water pipe into the water tank 42.

In detail, even with a small quantity of water supplied to the tray 201, the protruding portions of the freezing pipe 40 may be immersed at least a predetermined depth. Also, when the water supplied into the tray 201 reaches a preset water level, the pump 41 is turned off. Then, refrigerant that passes through the expander 35 flows through the freezing pipe 40.

Referring to FIG. 6, the low temperature, low pressure refrigerant flows to the freezing pipe 40 and exchanges heat with the water stored in the tray 201, so that the water stored in the ice making tray 201 begins to freeze. Here, at the point where freezing begins in the tray 201, the freezing begins on the surfaces of the protruding portions 401 of the freezing pipe 40. That is, freezing begins on the surfaces of the protruding portions 401, and the size of the freezing ice increases over time.

The protruding portions 401 are formed at predetermined intervals, so that as the ice forming on each of the protruding portions 401 increases in size, the respective ice formations may combine. Here, the supply of refrigerant to the freezing pipe 40 is discontinued right before the ice formations on the respective protruding portions 401 combine.

Referring to FIG. 7, freezing is stopped right before the ice formed on the respective protruding portions 401 of the freezing pipe 40 stick together, and the tray 201 is rotated to empty the remaining water from the tray 201.

In detail, at the moment that the tray 201 begins to rotate, a water collector 202 is positioned under the tray 201 to prevent the discarded remaining water from falling and flowing within the refrigeration compartment.

Here, the water collector 202 may be provided as a component of the ice maker 20 in connection with the tray 201, or may be a separate component provided below the ice maker 20. In other words, the water collector may be any structure that can be pulled out below the tray 201 at the moment the tray 201 begins to rotate, and restored to its original position when the discarding of the remaining water is completed, and thus, a description of the water collector 202 structure will not be given.

In another simple method for removing the residual water, a separate draining pipe for removing the residual water may be connected to the tray 201, and a draining pump may be connected to the other end of the draining pipe. When the freezing process is completed, the draining pump may be operated to remove the residual water.

Here, the pump 41 and the water tank 42 may be built into the inside of the refrigerator main body 11, or may be installed on an inner wall of the refrigeration compartment 15. The mounting structures of the pump 41 and the water tank 42 may be sufficiently resolved during the designing process of the refrigerator, and thus, a detailed description thereof will not be provided.

Referring to FIG. 8, after removal of the residual water is performed, the water collector 202 is restored to its original position, and the ice separation process is begun.

In detail, when the residual water is removed and the ice separation process is begun, high temperature, high pressure refrigerant flows to the freezing pipe 40, as shown in FIG. 4. Then, the temperature of the freezing pipe 40 rises, and the ice attached to the protruding portions separates. The separated ice 50 descends and is stored in the container 211 of the ice bank 21. As the structure of the ice bank 21 has already been described, a description of the ice bank 21 will not be provided.

If the size of the tray 201 and the size of the container 211 are different, or if the ice bank 21 is not directly underneath the ice maker 20, but provided to the front thereof, a separate guiding member may be provided to prevent the falling ice from falling outside the container 211. As in the example described above, the guiding member may extend from the opening of the container 211 toward the tray 201, or the guiding member may extend from the ice maker 20 toward the container 211 (refer to FIG. 2).

FIG. 9 is a perspective view showing a schematic structure of an ice maker according to a second embodiment of the present disclosure.

Referring to FIG. 9, an ice maker according to a second embodiment of the present disclosure is the same as that in the first embodiment, except for having a heater 50 for ice separation attached along the outer surface of the freezing pipe 40 instead of the separate freezing pipe and the return pipe structure for ice separation. Thus, descriptions of elements that are the same as in the first embodiment will be omitted hereafter.

To briefly describe an ice making process with the above structure, low temperature refrigerant flows to the freezing pipe 40, and water within the tray 201 freezes on the surfaces of the protruding portions 401.

At a predetermined point, either the tray 201 is rotated to remove residual water, or a draining pump operates to remove the residual water. The method for removing residual water has already been described in the first embodiment, and will therefore be omitted hereafter.

When the removal of residual water is completed, the tray 201 is rotated, and power is supplied to the heater 50 to generate heat. Thus, the ice frozen on the surfaces of the protruding portions 401 is separated, and the separated ice drops and is stored in the ice bank 21.

FIG. 10 is diagram showing a refrigerant cycle for an ice making system according to the second embodiment of the present disclosure.

Referring to FIG. 10, an ice making system in a refrigerant cycle according to the second embodiment of the present disclosure is the same as that of the first embodiment with the ice separation pipe 46, return pipe 47, the second valve 37, and the third valve 38 removed. It is also different to that of the first embodiment in that a heater 50 is installed on the surface of the freezer pipe 40.

FIGS. 11 to 14 are sectional views showing ice making and ice separating processes in an ice maker according to the second embodiment of the present disclosure.

Referring to FIGS. 11 to 13, in the present embodiment, the processes of supplying water to be made into ice, performing ice making, and removing residual water are the same as in the first embodiment, and therefore, descriptions thereof will not be given.

Referring to FIG. 14, after the residual water has been removed, and the tray 201 is rotated 180°, power is supplied to the heater 50, which begins generating heat. Thus, the ice attached to the protruding portions 401 is separated, and the separated ice falls into the container 211 of the ice bank 21.

In the above-structured ice making system, because there is no need to form a separate cold air passage to supply a portion of refrigerant for making ice to the ice maker, the refrigeration compartment or the freezer compartment can be expanded. In addition, because the freezing pipe 40 directly extends to the ice maker, and ice is formed directly on the surface of the freezing pipe 40, even if the ice maker 20 is directly exposed to the atmosphere in the refrigeration compartment, ice making can be performed properly. Also, because ice forms from the surface of the freezing pipe 40 progressively outward, transparent ice can be made. 

1. An ice making system for a refrigerator, comprising: a compressor compressing refrigerant; a condenser through which refrigerant that passes through the compressor flows; an expander expanding refrigerant that passes through the condenser to a low temperature and low pressure state; a tray provided within a refrigeration chamber to store water for ice making therein and move during at least an ice separation process; and a freezing pipe branched from an outlet of the expander and connected to an inlet of the compressor, and having at least a portion thereof immersed in the water stored in the tray, wherein ice is made directly on a surface of the freezing pipe.
 2. The ice making system according to claim 1, wherein in an ice making process, refrigerant expanded by the expander flows to the freezing pipe, and in the ice separation process, refrigerant that passes through the compressor or the condenser flows to the freezing pipe.
 3. The ice making system according to claim 1, further comprising a valve member provided at a point where the freezing pipe is branched.
 4. The ice making system according to claim 1, further comprising: an ice separation pipe branched from an outlet of the compressor or the condenser, and connected to an inlet of the freezing pipe; and a return pipe branched from an outlet of the freezing pipe, and connected to the outlet of the compressor or the condenser.
 5. The ice making system according to claim 4, further comprising: a first valve provided at the inlet of the freezing pipe; a second valve provided at an inlet or an outlet of the ice separation pipe; and a third valve provided at an inlet or an outlet of the return pipe.
 6. The ice making system according to claim 1, further comprising a heater attached to the surface of the freezing pipe.
 7. The ice making system according to claim 1, wherein the freezing pipe is bent a plurality of times to form a plurality of protruding portions, and at least a portion of the protruding portions is immersed in the water stored in the tray.
 8. The ice making system according to claim 1, wherein the tray is rotated in the ice separation process.
 9. An ice making system for a refrigerator, comprising: a tray filled with potable water for making ice, and provided in a space maintained at an above-freezing temperature; and a freezing pipe with at least a portion thereof immersed in the water filled in the tray, wherein in an ice making process, low temperature refrigerant flows to the freezing pipe, and ice is made directly on a surface of the freezing pipe.
 10. The ice making system according to claim 9, wherein in an ice separation process, high temperature refrigerant flows to the freezing pipe.
 11. The ice making system according to claim 9, further comprising a heater provided on the surface of the freezing pipe to generate heat during an ice separation process.
 12. The ice making system according to claim 9, wherein the tray is rotatably provided.
 13. The ice making system according to claim 12, further comprising a container provided on a rear surface of a door for opening and closing a space in which the tray is contained, wherein ice separated from the tray falls into the container.
 14. The ice making system according to claim 13, wherein a cold accumulating member surrounding surfaces of the container or a separate cooling device provided around the container maintains the container at a sub-freezing temperature.
 15. The ice making system according to claim 13, wherein a cold air duct, through which cold air is directly discharged into the container, maintains the container at a sub-freezing temperature.
 16. The ice making system according to claim 9, further comprising a water supplying device supplying water to the tray.
 17. The ice making system according to claim 9, wherein the freezing pipe is formed of a corrosion-resistant and rust-resistant material, or the freezing pipe is coated with a corrosion-resistant and rust-resistant material.
 18. A method for ice making in a refrigerator, the method comprising: collecting water for ice making in a tray provided in a refrigeration compartment, the tray containing a freezing pipe in a space within; immersing at least a portion of the freezing pipe in the water; forming ice on a surface of the freezing pipe by inducing a flow of low temperature refrigerant through the freezing pipe; removing residual water from the tray when the forming of the ice is completed; and detaching the ice formed on the surface of the freezing pipe.
 19. The method according to claim 18, wherein the forming of the ice is completed before adjacent formations of ice contact one another.
 20. The method according to claim 18, wherein the forming of the ice is completed before the water collected in the tray freezes in its entirety.
 21. The method according to claim 18, wherein the removing of the residual water is performed through rotating the tray.
 22. The method according to claim 18, wherein when the forming of the ice is completed, the removing of the residual water from the tray is performed with a draining pump.
 23. The method according to claim 18, wherein the detaching of the ice begins after at least the tray has been rotated.
 24. The method according to claim 18, wherein the detaching of the ice is performed by inducing a flow of high temperature refrigerant through the freezing pipe.
 25. The method according to claim 18, wherein the detaching of the ice is performed by heating a heating member attached to the surface of the freezing pipe.
 26. The method according to claim 25, wherein in the forming of the ice, the inducing of the flow of the refrigerant through the freezing pipe is stopped.
 27. The method according to claim 18, wherein in ice forming process, refrigerant at an outlet of an expanding member is supplied to the freezing pipe.
 28. The method according to claim 18, wherein in ice separation process, refrigerant at an outlet of a compressor or a condenser is supplied to the freezing pipe. 